Project description:Noncoding RNAs (ncRNAs) comprise an important class of natural regulators that mediate a vast array of biological processes, including the modulation of chromatin architecture. Moreover, artificial ncRNAs have revealed that the functional capabilities of RNA are extremely broad. To further investigate and harness these capabilities, we developed CRISPR-Display ("CRISP-Disp"), a targeted localization strategy that uses Cas9 to deploy large RNA cargos to specific DNA loci. We demonstrate that exogenous RNA domains can be functionally appended onto the CRISPR scaffold at multiple insertion points, allowing the construction of Cas9 complexes with RNAs nearing one kilobase in length, with structured RNAs, protein-binding cassettes, artificial aptamers and pools of random sequences. CRISP-Disp also allows the simultaneous multiplexing of disparate functions at multiple targets. We anticipate that this technology will provide a powerful method with which to ectopically localize functional RNAs and ribonuceloprotein complexes at specified genomic loci. Whole cell poly(A) selected RNA seq, from HEK293FT cells bearing lentivirally-integrated Gaussia and Cypridina luciferase reporter loci. Cells were transiently transfected with dCas9~VP64 alone, or with dCas9~VP and one of several modified sgRNAs,each targeting the Gaussia reporter.
Project description:Noncoding RNAs (ncRNAs) comprise an important class of natural regulators that mediate a vast array of biological processes, including the modulation of chromatin architecture. Moreover, artificial ncRNAs have revealed that the functional capabilities of RNA are extremely broad. To further investigate and harness these capabilities, we developed CRISPR-Display ("CRISP-Disp"), a targeted localization strategy that uses Cas9 to deploy large RNA cargos to specific DNA loci. We demonstrate that exogenous RNA domains can be functionally appended onto the CRISPR scaffold at multiple insertion points, allowing the construction of Cas9 complexes with RNAs nearing one kilobase in length, with structured RNAs, protein-binding cassettes, artificial aptamers and pools of random sequences. CRISP-Disp also allows the simultaneous multiplexing of disparate functions at multiple targets. We anticipate that this technology will provide a powerful method with which to ectopically localize functional RNAs and ribonuceloprotein complexes at specified genomic loci. RNA Immunoprecipitation (RIP) against FLAG-tagged Cas9 protein, coexpressed with a large pool of CRISPR RNAs bearing random internal insertions
Project description:RNA sequencing (RNAseq) can be used to assemble spliced isoforms, quantify expressed genes and provide a global profile of the transcriptome. However, the size and diversity of the transcriptome, the wide dynamic range in gene expression and inherent technical biases confound RNAseq analysis. We have developed a set of spike-in RNA standards, termed âsequinsâ (sequencing spike-ins), that represent full-length spliced mRNA isoforms. Sequins have an entirely artificial sequence with no homology to natural reference genomes, but align to gene loci encoded on an artificial in silico chromosome. The combination of multiple sequins across a range of concentrations emulates alternative splicing and differential gene expression, and provides scaling factors for normalization between samples. We demonstrate the use of sequins in RNAseq experiments to measure sample-specific biases and determine the limits of reliable transcript assembly and quantification in accompanying human RNA samples. In addition, we have designed a complementary set of sequins that represent fusion genes arising from rearrangements of the in silico chromosome to aid in cancer diagnosis. RNA sequins provide a qualitative and quantitative reference with which to navigate the complexity of the human transcriptome. Detailed transcriptomic analysis of a human cell-type with synthetic RNA spike-ins ('sequins'). Sequins were initially combined at equimolar concentrations (a "flat" mix) and sequenced neat (i.e. without any natural RNA added). We then prepared two staggered mixtures (Mix A & B) and sequenced them neat. Mix A was then spiked into total RNA extracted from the K562 cell-type. Finally, we prepared a staggered mixture of fusion sequins and sequenced it neat.